Catheter Distal Member with Variable Young's Modulus for Guide Wire Trackability
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Solution Overview
Problem
Conventional catheters have limited trackability along a guide wire due to the configuration of their distal members, which often result in being caught by obstacles within body cavities.
Innovation Solution
A catheter design featuring a cylindrical distal member with a bending portion located distal to the most distal end of the catheter body, where the Young's modulus of the bending portion is smaller than that of the proximal end, allowing for enhanced flexibility and trackability. This is achieved through a heat treatment process that adjusts thermal loads on different sections of the distal member, creating a tapered distal end and a more flexible axially intermediate part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the distal member is made more flexible to improve trackability, then the catheter can better follow the guide wire shape, but the distal member may become too soft and lose structural stability
Solution Approach 1:
The distal member is designed with non-uniform thickness, where the intermediate part has a smaller thickness than the proximal and distal end parts. This creates a local flexibility enhancement at the intermediate section while maintaining structural stability at the ends. The bending portion is specifically positioned at the intermediate part with reduced thickness to improve trackability without compromising overall structural integrity.
Solution Approach 2:
The distal member is segmented into three distinct sections along its longitudinal axis: a proximal end part, an intermediate part, and a distal end part. Each section has different thickness characteristics, with the intermediate part being thinner to create a bending portion. This segmentation allows different regions to serve different functions - the thicker ends provide structural support while the thinner intermediate section provides flexibility for tracking the guide wire.
2Ease of operation
If the bending portion is located at the most distal end of the catheter body, then the structure is simpler, but the trackability along the guide wire is reduced
Solution Approach 1:
The bending portion is pre-positioned at the intermediate part of the distal member, distal to the most distal end of the catheter body, rather than at the tip. This preliminary positioning of the bending section allows the distal end to extend beyond the bending portion and make contact with the guide wire first, enabling the bending section to subsequently flex and follow the guide wire's curvature, thereby improving trackability.
Solution Approach 2:
The invention changes the longitudinal positioning dimension of the bending portion from the traditional distal tip location to an intermediate location. By moving the bending portion to a different position along the longitudinal axis, the catheter creates a three-dimensional configuration where the distal end extends beyond the bending section, allowing the bending portion to effectively engage with and follow the guide wire's path.
3Ease of manufacture
If heat treatment is applied uniformly across the distal member, then the manufacturing process is simpler, but the desired flexibility gradient cannot be achieved
Solution Approach 1:
The heat treatment process is applied non-uniformly to different sections of the distal member. The intermediate part receives a different thermal load compared to the proximal and distal end parts, resulting in localized material property changes. This selective heat treatment creates the desired flexibility gradient, with the intermediate section becoming more flexible while the end sections maintain greater rigidity.
Solution Approach 2:
The heat treatment process modifies the physical parameters of the distal member by applying different thermal loads to different sections. By controlling the temperature distribution and thermal exposure time for each section, the material's mechanical properties (flexibility, Young's modulus) are changed locally. This parameter change through controlled heating achieves the desired flexibility gradient without requiring complex multi-step manufacturing processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The catheter achieves high trackability and crossability along guide wires, reducing the likelihood of curling and improving navigation through body cavities while maintaining flexibility and ease of manufacturing.
Implementation Method 1
a heat treatment step of performing a heat treatment for fusing a proximal end part of a distal member having a cylindrical shape to a catheter body
Implementation Method 2
a heat transfer step of transferring heat to the proximal end part through a heat transfer portion that has a cylindrical shape and that contracts by heat
Implementation Method 3
the heat transfer portion absorbs radiation and generates heat
Data Source
AI summary
A catheter includes a cylindrical distal member connected to a distal end part of a catheter body, and the distal member has a bending portion located distal to a most distal end part of the catheter body, the bending portion being a section that bends when an external force in a bending direction is applied to a distal end part of the distal member with the distal end part of the catheter body being fixed. The Young's modulus of the bending portion is smaller than the Young's modulus of the proximal end part of the distal member. A method for manufacturing the catheter includes performing a heat treatment for fusing the proximal end part of the distal member to the catheter body while adjusting a thermal load on an axially intermediate part of the distal member to be smaller than a thermal load on the proximal end part.